Oh no.....not another tread about Timing Belts......

Interesting article.

Also, as he stated, belt dressing has always been the worst possible thing you can do to a belt or any rubber part in an effort to "fix" it. It just makes it degrade a lot faster.

 

My Mondial QV 'broke' a cam belt at about 2000 rpm, not at high speed. I was told that the high speed valve train motion is much smoother than at low engine speeds where the belt is jerked as each cam lobe contacts its valve. FWIW, the belt didn't break. Rather, about 10 teeth sheared from the substrate. Upon close examination of the belt - now held in my garage as constant reminder and a source of encouragement - the edges of many more of the 'teeth' show the beginnings of shearing away. The failure, which occurred at the small diameter drive pulley, was sadly complete predictable; with 20/20 hindsight. $9000 spent nine years ago, to repair the engine.

 

Thanks for posting, however, the bolded above has me some comfort and concern.

According to mfgr, = 3 years, which is also their recommendation anyway[/]...Ferrari or other, as a conservative. One could say, it's to generate money for the belt mfgr, but they seem to be more in the zone with 3 years anyway....interesting to those that doubt the 3 year rule: and we know we'll hear from them...

But 'limited driving conditions'??? what did you tell them? Did you mention types of driving or duration or frequency? Not sure how to take this other than go with the conservative approach even in the best of 'limited driving'.

Now what bothers me is their 'visual inspection of the lateral cracking' which they say, if I read correctly, 'will tend to perform for some time': wow, how scientific and conclusive is that?!!?!!

Didn't say on a high revving engine or other stress that 'some time or should perform' would not present failure. I'm sure most here if seeing ANY cracking would replace right away even over the age minimum...know I would.

Lastly their last sentence, is failure if cracking on the rib side.

Hmmm, just saying I don't see how their recommendation of 'will tend to perform for some time', equates to caution when reading that last sentence.

Rik

 

Rik, et al., I read some of that article to be intended for non-interference engines. Break a belt on a non-interference engine and it will leave you stranded. Break a belt on an interference engine and it will leave you stranded AND BROKE. Trust me on this one. I wrote the repair check!

 

I thought that Ferrari Belts were originally supposed to last 5 years...with the "older" technology belt (think 1980s). But then I know they had the report out a few years ago stating every 3 years...with the "new" technology belt.

So, if belt technology is getting better and more reliable, why would we have lost two years between belt changes??

Thats my question....



PDG

 

And that's why this won't be the last thread on timing belts !

 

His entire statement was about serpentine belts, not timing belts. Their design, construction, application and purpose is very different.

Don't mix apples and oranges.

If you are going to title a thread about timing belts and waste all the bandwidth at least make it about timing belts and not serpentine belts.

 

From what I read in the Dayco replay I think they thought you were talking about the accessory belts? That's the alternator, a/c, water pump, and if you have them, the power steering and smog pump belts. On my car (348) my timing belt has teeth not ribs. So if you could ask them about how long a toothed (if that's even a word?) cam belt should last that would be good.

 

I think their advice in the first paragraph of their response says all we need to know.

 

I am going to buy all the belt manufacturers on this planet and shut them all down so in the future there will be no more belt threads.

 

Kinda hard to talk about belt life without also talking about bearing life.... The teeth sheer off the belt because something (seized tensioner bearing or cam bearing, for example) puts an excessive load on the belt.

Personally, my cars live in a moderate climate, are driven regularly but with modest miles (less than 3,000/yr.), and sit in a secure and heated garage so I'm good with 5 years or 15,000 miles, whichever occurs first. But that's just me.

 

Anyone make a gear drive set up to replace the belts all together?

 

Living this nightmare right now. My son's '87 Maxima suffered a tensioner bearing failure on Friday. I'm almost down to the bare block and am hoping against hope that I am not looking at a hole in one of the pistons. I know there is valve damage and no compression in one cylinder but there is so much metal in the number 6 hole that I am getting a little sick as the unveiling approaches - tonight. We talk so much about belts we neglect the tensioner bearings. In my opinion you shouldn't change one without the other, unless you are changing belts because they were nearly new but got contaminated. A new tensioner for this Maxima cost $50 !!!! but the last mechanic didn't change it when the belts were done !!!!!!! :-(

 

I have the solution: junk all of the cars that have belts. Buy 430s and it's replacement, put the old bodies on the new chassis. Dont' tell anyone you did that. Or if that doesn't work, just swap the engines. Probably cheaper in the long run with a big block chevy, or a 430 engine in an older body. If you figure 10k per belt service, you'd pay for the entire project in 10 years or so.

LOL

Art

 

$10,000 for a belt service? Art you been robbed. Did they use a gun to collect the bill? Even Jesse James doesn't charge that much. In this case on 308 or 328 you can probably get 6 or 7 belt changes for ten grand.

 

That can be the case. However, the trapezoidal belt teeth used in the 308/328 also shear because the corners of the teeth are high flex & high stress areas between the relatively rigid raised tooth and the relatively flexable low portion of the tooth. That's why the belt mfg's adopted the curved tooth profile which has much smoother stress distribution. The advantages of the curvilinear tooth design are well documentated in the Gates catalog.

2000YELLOW360,
I'll be happy to do your belt service for $9K, saving you $1k.

 

I have repaired quite a number of cars where the teeth were just sheared off leaving the circumference of the belt intact with no mechanical failure causing it. It is the standard failure mode. The shear strength of the teeth of the belt are what delivers the driving load and when they are old enough the rubber no longer has the strength to deliver it. The belt is MUCH stronger than the teeth themselves.

 

Question:
I know everyone focuses on belt design, but isn't the "premature" wear on these belts not really a function of the belt quality, but the engine design, loads, etc, which cause the belts to wear at an "accelerated" rate. People always say, my Toyota belt lasted ten years. Isn't that really apples to oranges though?
Maybe, like the 2nd gear when cold issue, some engines are more prone to "premature" belt wear than others?

I don't know the answers to these questions, but it seems everyone focuses on the belts themselves rather than the engine design.

Any thoughts?

 

You are correct but try telling that to an internet expert. Not too many belt drive cars out there operating 48 valves with rather stiff springs and steep ramps on belts that has to modes, long periods of inactivity or driven at 9/10ths. Also not too many cars out there operating 40 valves that spin up to 8500 as quickly and have to accelerate all those parts that quickly in the extreme heat of a 360 engine compartment. Not too many cars out there that are owned and driven for the express purpose of beating the crap out of the motor every time it is driven. The simple fact is most want to believe you really don't need to pay to maintain your toy and Ferrari is just trying to screw you for the benefit of a dealer that they really don't care if he lives or dies.

Its all very laughable for those of us who know the truth of the situation but what do I care? I make a lot more money fixing broken cars than maintaining good ones.

 

so of course the inverse or conservative approach is a means to prolong a belts life, like not redlining it and just, well, cruisin' ....with some 'sprited driving' in-between. Of course not ignoring the published change schedule.
r

 

Another interesting point Brian made is the tremendous heat in the engine compartment. I never really thought about it, but in the mid-engine cars, the engine compartment gets scorching hot. Much hotter than any other car I have ever owned. The effect of that heat reeks havoc on other rubber and plastic components in the compartment over time from what I have been told and shown. I can't imagine it not having an effect on the belts as well.

As for your point, I THINK whether you drive it conservatively or not, the engines very design puts more stress on the belts than a typical belt drive car. Add to that the engine heat, infrequency of use, etc, and it all would seem to add up to a shorter interval schedule. Ferrari engines, it appears, where not designed with low maintenance costs in mind, hence, it appears that appropriate care requires more frequent belt changes.